1. Technical Field
The present invention relates generally to systems used to chlorinate bodies of water, and more specifically to systems utilizing electrolysis for the electrolytic chlorination of water.
2. Description of Related Art
As is well known, swimming pools, spas, and the like, must be chlorinated to prevent accumulation of algae and bacteria, transfer of disease, and the like. Heretofore, such chlorination has been accomplished by depositing relatively large quantities of sodium hypochlorite into the water to be gradually dissolved over time.
Unfortunately, because this procedure is essentially a periodic single batch operation, the concentration of chlorine is never constant. In order to minimize the number of times necessary to deposit sodium hypochlorite in order to replenish depleted sodium hypochlorite, a significant amount of sodium hypochlorite, often much greater than that recommended for efficacy, is often added to allow a longer time between additions.
These batch addition operations result in high quantities of chlorine being released immediately after the sodium hypochlorite has been added and often causes the water to give off a strong and offensive odor that can make swimming unpleasant. Additionally, the high concentration of chlorine often results in bleaching bathing suits, towels, and the like. Further, a high concentration of chlorine often results in eye and skin irritation, and may even discolor the swimmers' hair.
On the other hand, before the next batch of sodium hypochlorite is added, the chlorine level may fall below a biologically effective level, thus allowing a buildup of bacteria and algae and facilitating the possible transfer of disease. Obviously, none of these effects are desirable.
In addition to the problems caused by batch methods of chlorine control, the particular application and requirements often vary from system to system or within the same system over a period of time, thus requiring a water treatment system capable of multiple configurations or capacities. To accommodate this need, a system may consist of either multiple water treatment systems with each system having specific operating characteristics, or a single water treatment system capable of variable operating characteristics.
Due to concerns about the space required to house multiple systems and the increasing energy costs necessary to operate such a system, it is often most economical, and thus preferable, to put into operation a single, configurable water treatment system capable of handling multiple chlorine output requirements.
Various attempts have been made to provide systems for improving the effective treatment of such bodies of water. Such systems may comprise electrolytic cells for dissociation of a salt to yield a bioactive agent, or may provide for periodic infusion into a body of water of chlorine, provided, for example, by a floating reserve of chlorine tablets. Examples of such systems may be seen with reference to British Patent Number 1,426,017 to Miles; U.S. Pat. No. 3,792,979 to Clinton; U.S. Pat. No. 4,869,016 to Diprose et al.; U.S. Pat. No. 5,460,706 to Lisboa; U.S. Pat. No. 5,468,360 to David et al.; and U.S. Pat. No. 6,821,398 to Von Broembsen.
Because of the variations in chlorine concentration caused by using the batch method, and the limitations in the ability of current art chlorination systems to be adapted to various applications, current chlorine treatments systems have not been entirely satisfactory.
Due to their generally simple design and construction, floating reserve systems are often limited in their capacity to handle multiple requirements. Even though small changes in chlorine output requirement may require simply adding or removing chlorine tablets, the process nonetheless presents many problems. For example, the volume and surface area of chlorine tablets contained within an operating floating reserve system change over a period of time, making it difficult to pre-determine the effect of a subsequent removal or addition of chlorine tablets.
Thus, to change the capacity of a floating reserve system within a specified range, it may become necessary to open the system several times to either add additional chlorine tablets or to remove excess chlorine tablets. This increases the amount of exposure the user has to the chlorine, the amount of time necessary to bring a system back online, the possibility of damaging the system, and the wear and tear on the seals separating the hazardous inner contents of the reserve from the general public.
Additionally, large changes to the capacity may require changing the volume of the floating reserve container, requiring further testing to determine a new baseline of operation to ensure that the changes made have produced the desired effect. This procedure also has the undesired effects mentioned previously with the added costs due to the additional tests.
Current art systems comprised of electrolytic cells for dissociation of a salt provide for increased variability and safety over floating reserve systems. One way to change the chlorine output capacity in an electrolytic cell system is to change the current and voltage across the electrolytic plates. This eliminates the chlorine exposure problem found in floating reserve systems and alleviates the requirement to open the system more than once.
Even so, changing the voltage and current often create undesired secondary effects. For example, increasing the plate current may cause current leakage between cells, or if leakage is already occurring, may exacerbate the problem by increasing the amount of leakage, further decreasing the efficiency of the system. Additionally, increasing the voltage and current increases the power consumption for a given configuration.
If changing voltage and current are not sufficient for a particular need, or the secondary effects described above become unacceptable, another means in which chlorine production capacity in an electrolytic system may be changed is to increase or decrease the total surface area of the electrolytic plates. This is normally accomplished by increasing or decreasing the number and/or size of the plates in the system. Changing the number or size of plates in currently known systems causes both physical and electro-chemical issues that must be addressed.
For instance, if a large increase in chlorine production capacity is required in currently known systems, a significant number of plates may have to be added, the size of the plates may be increased, or additional electrolytic chlorinators may need to be added in series, each approach being problematic. If electrolytic plates have been added or resized, the system itself may become too bulky or large to fit within a specific area. This may create an inefficient or ineffective use of space and may also reduce the possibility of standardizing overall system and/or housing size, increasing production costs.
In currently known systems, adding additional or resized plates may also cause a significant divergence in the physical stresses placed on the plate support system from one plate to another. Additionally, resizing or adding additional plates in currently known systems is often problematic in that the electrical requirements may be increased to a point beyond the capacity of the currently installed electrical power unit. The addition or resizing of plates in currently known systems may also create variations in fluid flow patterns between the cells, possibly creating uneven reaction rates from plate-to-plate, further reducing the efficiency of the system. Finally, if additional electrolytic chlorinator systems are added, the purchase and installation cost, the electrical and control requirements, the plumbing/piping needs, and the cooling requirements may all be significantly increased.
It will be apparent that none of the above-available water treatment systems provide the several benefits, features and advantages of the present invention. Specifically, none are seen to provide an electrode stack arrangement and design conducive to efficient electrode operation in a baseline configuration and, subsequently, upon further addition of electrode plates. Through the use of such a chlorinator, more efficient control of bioactive chlorination within a body of water may be maintained, while providing for multiple chlorine capacities and while utilizing space in a more efficient manner.